TLDR Some hair protein genes evolved early and were adapted for use in hair follicles.
The study investigates the evolution of keratin-associated proteins (KRTAPs), crucial for hair follicle development. Out of 93 KRTAPs in humans, 53 are linked to a human metallothionein, and 16 to occludin. The metallothionein-linked KRTAPs, which are larger, include high-sulphur and ultrahigh-sulphur KRTAPs, while the occludin-linked set includes tyrosine- and glycine-containing KRTAPs. The study found that metallothionein-linked KRTAPs appeared in increasing numbers as evolution advanced, starting from deuterostomia, with strong sequence similarity found in a sea anemone and a starfish. Occludin-linked KRTAPs arose later, with a homologous KRTAP found in snails. The presence of KRTAP antecedents in non-hairy animals suggests that some KRTAPs may have a physiological role beyond hair fibre characteristics. The researchers propose that these KRTAPs were co-opted by placodes to produce the first hair-producing cells, the trichocytes of the hair follicles.
7 citations,
May 2022 in “PLOS ONE” Certain genes and pathways are linked to the production of finer and denser wool in Hetian sheep.
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27 citations,
April 2017 in “British Journal of Dermatology” Hair loss involves immune responses, inflammation, and disrupted signaling pathways.
14 citations,
April 2016 in “PloS one” The KRTAP11-1 gene promoter is crucial for specific expression in sheep wool cortex.
65 citations,
September 2014 in “BMC genomics” Different hair types in mammals are linked to variations in specific protein genes, with changes influenced by their living environments.
46 citations,
June 2013 in “Journal of structural biology” High glycine–tyrosine keratin-associated proteins help make hair strong and maintain its shape.
November 2022 in “Research Square (Research Square)” Keratin-associated proteins have ancient origins and were used for different purposes before being adapted for hair in mammals.
Hair follicles can be used to quickly assess drug effects in cancer treatment.
4 citations,
December 2020 in “Mammalian genome” Harlequin mutant mice have hair loss due to low AIF protein levels and retroviral element activity.
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22 citations,
April 2020 in “Scientific reports” Changthangi goats have specific genes that help produce Pashmina wool.
2 citations,
September 2022 in “Frontiers in genetics” Different proteins are linked to the varying thickness of sheep and goat hair types.
